Amine synthesis via condensation reactions between organic hydroxy compositions and ammonia or an amine resulting in a loss of a molecule of water is well known in the art. Certain such reactions are generally effected in the presence of acidic catalysts. One important area in which such acid catalysis has been employed is in cyclization reactions, as in the synthesis of triethylenediamine (sometimes referred to as TEDA) and its substituted homologues. The following patents are representative of cyclization reactions.
U.S. Pat. No. 2,937,176 discloses the preparation of TEDA by passing an aliphatic amine, such as an alkylene polyamine or alkanolamine over an acidic silica-alumina catalyst at a temperature from 300.degree.-500.degree. C. Diethylenetriamine and N-2-hydroxyethylethylenediamine are noted as being representative reactants for conversion to TEDA.
U.S. Pat. Nos. 2,985,658 and 3,166,558 disclose the preparation of TEDA by effecting condensation of N-aminoethylpiperazine over an acidic silica-alumina catalyst or an activated kaolin catalyst.
U.S. Pat. Nos. 3,172,891; 3,342,820; and 3,297,701 disclose the preparation of TEDA by reacting hydroxyethoxyethylamine with ammonia or the C-alkyl derivatives of TEDA by reacting hydroxyalkyl alkylpiperazine derivatives at a temperature from 250.degree.-500.degree. C. in the presence of an aluminum phosphate catalyst. U.S. Pat. No. 3,342,820 discloses the use of aluminum phosphate containing an alkali metal as a catalyst for the condensation reaction and alleges enhanced activity. Other examples of trivalent metal phosphates having catalytic activity include boron, bismuth and iron phosphates. U.S. Pat. No. 3,297,701 suggests additional metal phosphate catalysts can be used for effecting the condensation reaction and these metal phosphates include iron phosphate, zinc phosphate, nickel phosphate, copper phosphate, chromium phosphate and cobalt phosphate.
U.S. Pat. No. 4,117,227 discloses the preparation of substituted morpholine compositions by reacting an N-substituted diethanolamine over a phosphorus containing substance. Specific reactions illustrate the conversion of triethanolamine to hydroxyethylmorpholine or dimorpholinodiethylether. Various alkyl and aryl substituted phosphorus and phosphoric acids are alleged as being suited as catalysts and specific catalysts include methylphenylphosphonate, phenylphosphinic acid and ethylphosphonic acid.
U.S. Pat. No. 4,405,784 discloses the preparation of TEDA from hydroxyethylpiperazine and from diethanolamine by effecting a condensation reaction over strontium hydrogen phosphate. Dimethylaminoethylmorpholine was also produced over strontium hydrogen phosphate by condensing dimethylethanolamine with morpholine.
Intermolecular condensations between a hydroxy compound and ammonia or an amine to form coupled or cyclic compositions are also known. Representative patents showing the preparation of alkyl amines, polyamines and morpholine are as follows:
U.S. Pat. No. 3,383,417 discloses the intermolecular condensation of monoethanolamine with itself at pressures from 2000-4000 psig in the presence of a reductive amination catalyst. It has use as a dispersant for lubricating oils, a textile conditioner, a nonionic surfactant for shampoo and hair rinses.
U.S. Pat. No. 4,036,811 is representative of techniques for producing polyalkylene polyamines where, for example, monoethanolamine is reacted with ethylenediamine in the presence of a phosphorus-containing composition such as the alkyl and aryl phosphonates. In addition acidic metal phosphates, such as boron phosphate, ferric phosphate, and aluminum phosphate are suggested as being suited for effecting the reaction.
U.S. Pat. Nos. 4,103,087: 4,095,022 and 4,049,657 disclose the preparation of a variety of heterocyclic amines by reacting a disubstituted aminoalkanol in the presence of an acid metal phosphate catalyst, e.g., aluminum phosphate or phosphoric acid compound. The '022 patent shows the reaction of a hydroxyalkylmorpholine to produce the bis-morpholino-N-alkyl-ether, the reaction being carried out in the presence of an acid metal phosphate. U.S. Pat. No. 4,049,657 produces N-aminoalkylpiperazine by reacting piperazine with a primary or secondary aminoalkanol in the presence of a phosphorus-containing substance such as an alkyl or aryl phosphinate or acidic metal phosphate.